Volume control apparatus for recording and broadcasting



Jan. 3, B, w N v 1,893,291

VOLUME CONTROL APPARATUS FOR RECORDING AND BROADCASTING Filed Jan. 5. 1931 BERNARD KWARTIN uZ/Jorngy.

III/1167x607.-

Patented Jan. 3, 1933 UNITED STATES aaeaaai PATENT? BERNARD KWARTIN, OF BROOKLYN, NEW YORK Application filed January 5, 1931. Serial No. 506,522.

trol the volume of the sounds transmitted forrecording and broadcasting purposes. As is well-known by those familiar with the art to which this invention appertains, the sounds to be transmitted have been translatedby means of a microphone into electric currents varying in accordance with the sounds as originally produced, these currents being suitably amplified and transmitted through a-sound transmitting circuit. In so translating the initially produced sound vibrations into corresponding electrical variations, it has been the usual practice to employ a microphone the position of which is relatively fixed with respect to the source of the sounds an originally produced. Inasmuch as these sounds vary considerably in their strength or volume it was only natural thatunless ste s were taken to change the position of t e microphone relatively to the source of sounds, any sudden and marked increase in "the volume of the sounds would result in overloading the microphone. this overloading of the microphone, the transmitted sounds are not only distorted but also cause annoying and disagreeable blasts in the sound reproducing devices.

Not only are the foregoing conditions prescut where the sounds as originally produced are broadcast by radio but they are also present where the sounds are converted into electrical variations for the purpose of recordin the same upon photographic -filmsor otfier records, it being obvious that where the sounds as originally produced are to be recorded for purposes of subsequent reproduction the recording devices are influenced by the current variations established in the microphone circuit and that when the microphone is subjected to a sudden blast or increase in the volume of the sounds the current set-up-in the microphone circuit is correspondingly increased. These objections have been of course appreciated by those In consequence of skilled in the art and/while various attempts have been made from time to time to overcome the same no really satisfactory solution to the problem has as yet been advanced. One

solution which has been in more or less general practice has been for the artist speaking or singing into the microphone to move away from the microphone upon his increasing the volume of the sounds produced by him or conversely moving the microphone away from the source of the sounds as the volume thereof is increased. Such expedients are but makeshift ones and can hardly be satisfactory to a maximum degree because of the fact that they must depend upon the broadcaster or an operator to positionally adjust the microphone accordingly as the volume of the sounds is increased or decreased.

It is. among theprincipal objects of this invention to obviate the aforementioned 0bjections and diificulties by providing an arrangement whereby the position of the microphone employed for transmitting the sounds is automatically adjusted in accordance with the variations in the volume of the sounds initially produced, thereby eliminating the necessity for manually adjusting the position of the microphone.

Still another object of the invention is the provision of an apparatus or system which is automatically operable to preclude the ossibility of the sound translating device eing subjected to a sudden blast of sound.

Still another object of the invention is the provision of an arrangement for controlling 1 the volume of transmitted sounds which in- -cludes a primary microphone and means controlled by this primary microphone for gova erning the extent to which a secondary microphone is influenced by the initially produced sound vibrations.

, Other objects of the invention and advantz;ges thereof will appear more fully hereina er.

The invention consists substantially in the combination, construction, location, nd relative arrangement of parts, all as w' 1 be de scribed more fully hereinafter, as shown more or less diagrammatically in the accompanying drawing and as finally pointed out in the appended claims. In the said accompanying drawing y Figure 1 is a more or less diagrammatic view showing one form of an arrangement for positionally adjusting a secondary microphone automatically'in accordance with the volume of the sounds as originally produced;

Figure 2 is a diagrammatic view of a modified form of the invention;

Figure 3 is a view taken on the line 3-3 of Figure 2; y

Figure 4 is a diagrammatic View of a still further modified arrangement embodying the principles of this invention and which includes a secondary microphone having operatively associated therewith a shutter or screen which is movable automatically in accordance with the volume of the sound as originally produced;

Figure 5 is an elevational view of one form of the movable screen shown in Figure 4. Referring now to the drawing and more particularly to Figure 1 thereof it will be observed that the arrangement includes a primary microphone 10 which may be supported in relatively fixed position upon a suitable standard 11. This primary microphone 10 is included in any suitable type of amplifying circuit 12, it being understood that the sound vibrations receivedv by the microphone 10 are converted thereby into electrical currents which vary in accordance with the sounds as originally produced. Suitably coupled to or included in the circui't 12 is a solenoid 13 having a movable armature or plunger 14. It will be apparent that the energization of the solenoid 13 is entirely dependent upon the current variation established in the primary microphone circuit 12 and that the armature 14 is movable in accordance with these current variations.

Suspended immediately above the primary microphone 10 by means of a wire 15 or the like is a secondary microphone 16. It will be observed that this secondary microphone 16 is electrically independent of the primary microphone 10, although it is subjected to the same sound vibrations to which the primary microphone is subjected. As is clearly indicated in igure 1 the secondary microphone 16 is connected by means of the conductors 17 to any suitable sound transmitting circuit. It will be understood of course that if the initially produced sounds are to be broadcast by radio the output of this sound transmitting circuit would be connected inthe usual manner to the antenna of the transmittin station. On the other hand, if the initial y produced sounds are to be recorded for subsequent reproduction, the output of this transmitting circuit for the secondary microphone 16 would be connected as in the usual manner to the particular sound recordmg device or devices employed. Or, if the arrangement is to be employed in connection with sound address systems wherein it is merely desired to amplify the sounds as originally produced, the output of the secondary sound transmitting circuit would be connected to the usual loud speaker or other such sound reproducing devices.

The secondary microphone 16 is mechnnically connected to the movable armature 14 of the solenoid by means of a wire 17 or the like, it being understood that as the armature assumes various positions accordingly as the solenoid 13 is variably energized, the secondary microphone 16 will. likewise be caused to assume various positions. It will thus appear that the position of the secondary microphone 16 is automatically varied in accordance with the volume of the sounds as originally produced and to which both the primary and secondary microphones are subjected. Thus, where the volume of the initially produced sound is suddenly and considerably increased, the solenoid 1s cor- A respondingly energized to an extent suiiicient to pull the armature 14 to the right and so move the secondary microphone 16 away from the source of the sounds. With a decrease in the volume of the sound, the solenoid 13 is correspondingly deenergized i the secondary m1croconsequence of which phone 16 is permitted, through its own weight, to move back toward the sound source. I

It will of course be understood that in the arrangement hereinbefore described and in those to be described hereinafter, the originally produced sounds are transmitted for broadcasting, reproduction or recordation only by means of the secondary microphone and that the primary microphone is employed only as a means for insuring automatic positional adjustment of the secondary microphone accordingly as the volume of the originally produced sound is varied. Instead of employing a secondary microphone which is suspended for bodily movement toward and away from the sound source, an arrangement such as is shown in Figures 2 and 3 may be employed.

, In this modified arrangement a relatively fixed primary microphone 10 1s again employed for efiecting energization of the solenoid 13. Operatively associated with the primary microphone 10 and adapted to be subjected to the same sound vibrations which are received by the latter is a secondary microphone 18. This secondary microphone 18 is supported at the lower end of a vertically extendin stem 19 the upper-end of which is suitab y journalled, as at 20, to permit the oscillation of said stem about its vertical axis. Fixed to this stem 19 at a suitable point above the secondary microphone 18 supported thereby is a pinion 21. Adapted for mesh engagement with this pinion 21 is a reciprocating rack 22. By forming this rack 22 as the movable armature of the solenoid 13 it will be apparent that it will be caused to reciprocate accordingly as the solenoid is energized or de-energized. Any suitatable spring means (not shown) may be eniployed for retracting the rack 22 when the solenoid 13 is partially or completely de-energized. I

In the arrangement shown in Figures 2 an 3, it will be seen that the secondary microphone is caused to oscillate accordingly as the initially produced sounds are increased or decreased in volume in such manner that the sound receiving surface thereof assumes various angles with respect to the vertical plane intersecting the axis of oscillation of the secondary microphone and the center of the sound source. Thus, when the sounds are of great volume the sound receiving surface of the secondary microphone assumes a considerable angle with respect to said vertical plane, whereas, when the sounds are reduced to their minimum volume the sound receiving surface of the secondary microphone assumes a position whichis substantially normal to said vertical plane.

In some instances, it may not be desirable to employ a secondary microphone which is positionally adjustable as in the arrangement of Figures 1 and 2. Figure 4 accordingly shows a still further modified arrangement of the present invention wherein the primary microphone 1O as Well as the secondary microphone 23 are mounted in relatively fixed position with respect to the sound source. As in the former arrangements, both the primary microphone 10 and the secondary microphone 23 are simultaneously subjected to the samesound vibrations. Also as in the former arrangements, the primary microphone 10 is employed to energize the solenoid 13 accordingly as the volume of the initially produced sound is i creased or decreased. Adapted to be actua ed by the solenoid 13 accordingly as the latter is energized by the current "ariation established in the primary microphone circuit 12 is a shutter or screen 24. 4

As appears quite clearly in Figure 4 this shutter or screen 24 is disposed immedately in advance of the secondary microphone 23 and is adapted to be raised or lowered depending upon the energization of the solenoid 13*. This shutter or screen 24, which may be constructed inany suitable manner to provide the desired results, preferably comprises a frame 25 across which is stretched in more or less taut manner a sheet of fabric 26 or similar material. This material 26 is so fabricated or treated as to provide differentzones or areas of varying sound transmitting quality. In the particular instance illustrated in Figures 4 and 5, the material 26 of the screen is so treated that the upper portion thereof is of maximum sound transmitting quality while the lowest portion or area thereof is of minimum sound transmitting quality, the sound transmitting quality of the intermediate portion thereof varying gradually from said'maximum to said minimum. In other words, the screen 26 gradually decreases in its sound transmitting quality beginning with the up per end thereof toward the lower end thereof. Thus, in the arrangement of Figure 4, when a great volume of sound is suddenly directed against the microphones 10 and 23, the solenoid 13 is immediately operative to cause the shutter or screen 24 to assume a position such that the portion thereof of poorest sound transmitting quality is effective to intercept the sound waves which would ordinarily have been directly received by the secondary microphone 23. This, of course precludes the possibility of the secondary microphone 23 being subjected to sudden and sometimes uncontrollable blasts of sound. Obviously, when the sounds decrease in volume the shutter or screen 24 is lowered to a position such that the portions thereof of greatest sound transmitting quality intercept the sound waves.

It will be understood of course that the arrangements hereinbefore described are sus; ceptible of various changes and modifications without departing from the real spirit or general principles of the invention. For example, in the arrangement shown in Fig ure 2, instead of employing a rack and pinion for causing an oscillatory movement of the secondary microphone 18, a. cord may be employed which is Wrapped around a pulley carried by the stem 19, the opposite ends of this cord being respectively secured to this pulley and to a movable armature of the solenoid 13. In such an arrangement, which is not herein shown, any suitable spring means may be employed to keep the cord wound about thepulley against the action of the energized solenoid. In view of these possible changes it is intended to claim the invention broadly, as Well as specifically, as indicated by the appended claims.

What is claimed as new and useful is 1. In a sound transmitting system, a device for converting sound vibrations into corresponding electrical current variations, and

means controlled by the volume of the sound vibrations for positionally adjusting said device with respect to the source of the sound vibrations.

2. In a sound transmitting system, a device for converting sound vibrations into corresponding electrical current variations, and means operatively associated with said device for positionally. adjusting the same automatically in accordance with the volume of the sounds originally produced.

3. In a sound transmitting system, a primary microphone, a secondary microphone,

sponding electrical current variations, an

both of said microphones being adapted to receive the same sound vibrations, means for converting the sound vibrations received by said primary microphone into corresponding electrical current variations, and means influenced by said electrical current variations for Varying the degree to which said secondary microphone is influenced by said sound vibrations. I

4. The method of governing the extent to which a sound translating device is subjected to sound vibrations of varying volume which consists in subjecting a separate sound translating device to the said sound vibrations whereby to convert the latter into correin utilizing said electrical variations for varying the sound receiving capabilities of said first-mentioned sound translating device.

5. The method of controlling the volume of transmitted sound which consists in receiving the sound as originally produced by a sound translating device which is capable of converting the sound vibrations into corresponding electrical current variations, in maintaining a fixed relation between said sound translating device and thesource of. said sound, in subjecting a second sound translating device to the same sound vibrations, and in utilizing the current variations est-ablished by said first-mentioned sound translating device for varying the sound receiving capability of said second sound translating device.

6. In an arrangement for transmittitng sound, a pair of electrically independent sound translating devices, arranged to simultaneously receive the same sound vibrations, both of said devices being adapted to convert the sound vibrations into corresponding electrical current variations, and electromagnetic means adapted to be variabl energized by the current variations esta lished by one of said devices for efi'ecting positional adjustment of the other of said'devices, such positional adjustment bein in accordance with the volume of the initially produced sound vibrations.

7. In an arrangement for transmitting sound, a device for receiving sound waves and for converting the same into correspondin electrical current variations, the position 0 said device being relatively fixed with respect to the source of the sounds as originally produced, a second device for receiving the same sound waves and for converting the same into electrical variations, said second device being electrically influenced by said first device for positionally adjusting said second device with respect to the source of the sound waves. j a

8. In an arrangement for governing the volume of transmitted sound, a relatively stationary sound translating device adapted to d by the receive and convert sound vibrations into corres ending electrical current variations, a secon sound translating device for receiving the same sound vibrations, and means automatically operative in accordance with the volume of the-sounds received by said first-mentioned device for justing said second device wi source of the sounds.

9. In an arrangementfor transmitting h respect to the sounds, a device for converting sound vibration into corresponding electrical current variations, a shutter operatively associated with said device and'having diiferent sound transmitting qualities, and means controlled volume of the sounds as originally produced for positionally adjusting said shutter relatively to said device accordingly as the volume of saidsounds is altered.

10. In an arrangement for controlling the sound loading of a sound transmitting depositionally ad- I vice capable of converting sound vibrations emanating from a given source into correspond-ing electrical current variations, means operable automatically in accordance with the variations in volume of the sounds as originally produced for varying the degree to which said device is influenced bythe sound vibrations emanating from said source.

I In testimony whereof, I have hereunto affixed my signature.

BERNARD KWARTIN. 

